Internal combustion engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, operate by converting heat energy of fuels to kinetic energy. In an internal combustion engine, burning of a fuel occurs in a space called a combustion chamber. This burning of fuel creates gases of high temperature and pressure, which expand to cause movement, for example by acting on one or more pistons interconnected by connecting rods to a crankshaft, and are typically disposed to reciprocate within cylindrical bores (cylinders) formed in a crankcase. The expansion of the gases produced during combustion applies force to the piston. An open end of the cylinder permits reciprocating movement of the piston within the cylinder. A crankshaft connected to the piston converts the linear motion of the piston (resulting from the combustion of fuel in the combustion chamber) into rotational motion.
The combustion chamber of an engine may comprise a cylinder bore, a cylinder liner, a piston disposed within a cylinder bore, a fuel injector surrounded by an injector sleeve that is disposed in a cylinder head that may have one or more coolant passages through which water or a coolant may flow. In general, a piston is formed to have a generally cupped shape, with the piston head forming the base of the combustion bowl, and the skirt portion being connected to the base and surrounding an enclosed gallery of the piston. A piston skirt typically includes a pin opening and other support structures for connection to the connecting rod. The piston crown, together with the walls of a cylinder or a cylinder liner, in which the piston reciprocally moves, and the cylinder head, delimit a combustion chamber.
Many piston designs are known in the art. For example, U.S. Pat. No. 9,416,750 B2 (Bischofberger), discloses a piston for an internal combustion engine that has an piston head that has an insert made of an annular component and that is held in the piston head by means of an undercut section. The annular component has an inner wall on the piston bowl side, and the inner wall continuously tapers off all the way to the bowl wall or the bowl base in a flush manner to form a circumferential edge that tapers into a point. While the piston disclosed in the '750 patent may increase the piston's tolerance of stress and may reduce the risk of crack formation in the piston head, the need for piston designs that are designed to deal robustly with over-pressures arising from the presence of incompressible liquid in the combustion chamber is apparent. The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.